http://www.sm0vpo.com/blocks/if-txfmr_tube_00.htm
and
http://www.sm0vpo.com/begin/cans-0.htm

/Harry

"raypsi" wrote in message
...
On Aug 25, 1:12 pm, Howard James wrote:
Hey OT:

I seen one web site, wound if coils on 1/2inch PVC, turns were 65
turns for the grid and 150 turns for the plate they used a ferrite rod
or antenna rod for a tuning slug. put the coils in a tin can for like
soup;

Another site they used 2, 1mh coils in close proximity and tuning with
trim caps, all put in a cast aluminum box.

Both those idea's bigger than the old 3/4in sq can of old.

Trying to find treaded slugs could be a chore even it you wanted to
dup the old cans,

Trouble with the surplus stuff you don't know if it is 455 or 10.7
unless you test it or take it apart.

73 OT:

de n8zu




I'm about to embark on a "vintage" valve (tube) receiver but have a
question (probably more questions later!!!) about the IF transformers.
Years ago I was able to purchase the transformers for 455 KHz but the
ones I want are for 9 MHz. I think I'll have to wind them. I don't have
any 10.7 MHz transformers. Any advice appreciated. I'm really interested
in the turns ratios as I'll be winding the primaries for a Q of about
100.
Do the inter-IF amp windings have the same turns ratio as the balanced
modulator detector transformer? I think not. Do I have to worry about
turns ratio for anode impedance to grid impedance and what are "rule of
thumb" ratios? Can I use FTxx toroids as opposed to say quarter inch
coil formers with screening cans? So many questions. It's great being a
radio amateur!
Thanks. Howard.